[test] Smooth.SineSurface fails - the difference between prop3.volume and 8.43 exceeds 0.01

[cjmayo]

Not for merging

 [ RUN      ] Smooth.SineSurface
/home/runner/work/manifold/manifold/test/smooth_test.cpp:361: Failure
The difference between prop3.volume and 8.43 is 0.012265510559082315, which exceeds 0.01, where
prop3.volume evaluates to 8.442265510559082,
8.43 evaluates to 8.4299999999999997, and
0.01 evaluates to 0.01.
[  FAILED  ] Smooth.SineSurface (17 ms)

Appears to happen only when both -march and -O are used.

Something is setting -O3 here, but I can reproduce with -march=x86-64-v3 -O2 and -march=znver2 -O2, on GCC 13 and 14 respectively.

manifold-2.5.0 passes all tests with -march and -O.

[elalish]

Looks like I just didn't update the number accurately - I'm getting 8.438 locally, so the check ought to be 8.44. Want to update it and check it's okay? This looks like some rounding error from doing ops in a different order probably. Let me know if you actually notice something ugly in the resulting shape: ./manifold_test --gtest_filter=Smooth.SineSurface -e

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.71%. Comparing base (d437097) to head (19428c5).
Report is 52 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #848      +/-   ##
==========================================
- Coverage   91.84%   89.71%   -2.13%     
==========================================
  Files          37       62      +25     
  Lines        4976     8858    +3882     
  Branches        0      961     +961     
==========================================
+ Hits         4570     7947    +3377     
- Misses        406      911     +505     

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[cjmayo]

8.44 works. Not exactly sure what to look for but nothing obviously irregular in the shape.

[elalish]

Care to simplify the PR to that one-liner?

[cjmayo]

Test commit dropped. Still passes; good to go.

[elalish]

Thanks!